As is well known, a substance that is a factor for causing an allergic symptom is called allergen or antigen. Pollen and house dust, such as mold, mold spore, mite body, and mite feces, can be mentioned as allergen. Normally, an immunologic reaction (self-defense reaction) works advantageously for protecting the human body from these foreign substances, but allergic symptom is resulted when the immunologic reaction works disadvantageously. When leading a stressful life, i.e., becoming extremely nervous in social and daily lives, one could gradually disrupt the function of autonomic nerves and lose hormonal balance. This is believed to be a state in which allergy is likely to manifest. In addition, as another factor which is likely to cause an allergic symptom, there can be mentioned a closed living environment in which an amount of house dust as a predominant allergen is increased.
For the measurements against allergy (such as pollen allergy) to this day, the exposure to pollen has been suppressed to minimum, by using a mask or goggle with high sealing effect for blocking pollen or a dust collector or air purification device for removing pollen. When allergic symptom is manifested, nose or eyes has been washed, and therapeutic medicine for alleviating a symptom has been administered. Use of therapeutic medicine is merely a temporal suppression of the symptom, and it should be administered every time the symptom appears, and thus there is concern that a side effect might occur.
Recently, as a method for preventing pollen allergy, there has been proposed a method in which the pollen allergy allergen is treated with alkali, acid and protease under heated conditions (see Patent Document 1).    Patent Document 1: Japanese Patent Application JP2004-89673A